Lee -
It depends on how you're looking at it. If you're trying to figure
out the production rate once you've started running, it would simply be
100 parts per hour (or 1/100 = 0.010 hours per part). But if you want
to know the production rate for a particular order, you need to know
the total number of parts being produced (1000, in your example) and
the total amount of time it would take to make them (1 hour setup + 10
hours run-time = 11 hours total). So the production rate for that
particular order would be 1000 parts / 11 hours = 90.9 parts per hour.
(Or 1/90.9 = 0.011 hours per part).
To figure this out in percent, you first have to know what the
maximum possible is. In this case, we can say that the highest
concievable rate of production would be 100 parts per hour. So we just
divide the particular rate of production by this (and multiply by 100%)
to get the percent efficiency for that particular order:
(90.9 parts/hr) / (100 parts/hr) * 100% = 90.9% efficiency
OR...
(parts/hr produced) / (max. parts/hr possible) * 100%
One thing that I think is interesting to notice is that because of
your one hour set-up time, your percent efficiency will get higher and
higher as the size of your order increases. Take, for example, orders
of 100 parts, 1000 parts, and 10,000 parts:
For 100 parts, it will take 1 hour to setup and 1 hour to run, so
the rate of production is 100 parts / 2 hours, or 50 parts per hour. So
the efficiency is:
(50 parts/hr) / (100 parts/hr) * 100% = 50% efficiency
We already figured out that for 1000 parts, it's 90.9% efficiency.
And for 10,000 parts, it takes 1 hour to setup and 100 hours to
run, so the rate of production is 10,000 parts / 101 hours, or 99 parts
per hour. So we get:
(99 parts/hr) / (100 parts/hr) * 100% = 99% efficiency
And all together:
100 parts: 50% efficiency
1000 parts: 91% efficiency
10,000 parts: 99% efficiency
I hope this helps to answer your question!
-Tamara
(published on 10/22/2007)
